Nonlinear line of weakness formed by a perforating apparatus

ABSTRACT

A web may include a curvilinear line of weakness comprising a plurality of perforations and a first amplitude. The first amplitude may be less than a second amplitude of a perforating apparatus that formed the sinusoidal-shaped line of weakness comprising the first amplitude.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of, and claims priority under 35U.S.C. § 120 to, U.S. patent application Ser. No. 15/984,820, filed onMay 21, 2018, which is a continuation of U.S. patent application Ser.No. 14/301,415, filed on Jun. 11, 2014, now U.S. Pat. No. 10,005,197,granted Jun. 26, 2018, which claims the benefit, under 35 USC § 119(e),of U.S. Provisional Patent Application Ser. No. 61/834,126, filed onJun. 11, 2013, the entire disclosures of which are fully incorporated byreference herein.

FIELD OF THE INVENTION

The present disclosure relates to nonlinear lines of weakness for rolledproducts, and more specifically, relates to a web comprising a nonlinearline of weakness comprising one or more perforations and one or morebond areas.

BACKGROUND

Many articles and packages include or can include a strip of materialthat has a line of weakness having one or more perforations to aid intearing the article or package. For example, articles can include waxpaper, aluminum foil, disposable bags, and sanitary tissue products,such as toilet tissue, facial tissue, and paper towels manufactured inthe form of a web. Sanitary tissue products include lines of weakness topermit tearing off discrete sheets, for example, as is well known in theart. Such products are commonly used in households, businesses,restaurants, shops, and the like.

Typically, a line of weakness consists of a straight perforation acrossthe width of the web. Creating perforations at high speeds and longwidths is very challenging. Small vibrations in the equipment can resultin non-perforated areas and/or inconsistent quality in the perforationand/or additional wear on the equipment. Further, tight tolerancesbetween equipment must be maintained. Generally, there are three ways toperforate webs: die cutting, laser cutting, and flex blade cutting. Diecutting is a compression or crush cut in which a knife contacts ahardened anvil roll or a male roll interacts with a female roll tocreate one or more perforations. Die cutting usually is associated withhigh replacement costs and low speeds. Further die cutting does notallow for accuracy at long widths or mismatched speed operation.Similarly, laser cutting is a high-powered method to perforate webs.Laser cutting is usually used on thicker substrates and on cutsrequiring a high degree of accuracy. Still further, flex blade cuttingis a cut created by shearing the web. Flex blade cutting requires atleast one blade to flex against a relatively stationary blade or anvilduring operation to cut the web. Relative to the above cutting methods,flex blade cutting is generally lower cost, can be performed at higherspeeds, and can be run at mismatched speeds. In addition to the above,water jet, steam, and spark aperture cutting methods can also be used tocreate lines of weakness. These methods have been found to beincompatible with the product being manufactured and/or inadequate forhigh speed, low cost production of perforated webs.

For example, using two rotating rolls to create a shaped line ofweakness can be complex and expensive. The two rotating rolls must bematched to come together at exactly the right moment in time. Statedanother way, the male roll must be synchronized with the female roll.Further, creating perforations with a rotating male roll and a rotatingfemale roll can require a greater force be imparted to the web to createthe line of weakness. Finally, the equipment to create such a line ofweakness is large and must operate at lower speeds to maintain propermatching of the rolls.

It has been found that consumers desire products that are usable andhave a distinguishing feature over other products. Manufacturers ofvarious products, for example sanitary tissue products, desire thatconsumers of such products be able to readily distinguish their productsfrom similar products produced by competitors. One way a manufacturercan distinguish its products from other products is to impart physicalcharacteristics into the web that differ from other manufacturers'products. A shaped perforation is one distinguishing characteristic thatcan be added to the product. The shape of the line of weakness would notonly provide a way for consumers to distinguish a manufacture's product,but also communicate to consumers a perception of luxury, elegance, andsoftness and/or strength.

Further, manufactures desire a shaped perforation that consumers of suchproducts can easily and readily interact with. Often a straightperforation on a sanitary tissue product, for example, can rest directlyon the adjacent layer making it difficult to see the end of the sheet.This can make it difficult for a user to locate, grasp, and/or dispensethe product. A straight perforation can allow for only a single plane ofthe product on which a user can grasp for dispensing.

However, producing a web with a shaped perforation adds more complexityto the manufacturing process. As previously stated, tight tolerances andminimal to no vibration are required in manufacturing a line of weaknessat the high speeds necessary for commercial viability. Thus, adding ashape to the anvil and/or the blade can increase the risk of introducingprocessing complexities and complications into commercial manufacturingoperations for a perforated web.

Still further, as previously stated, consumers desire a product thatthey can easily and readily interact with. A shaped perforation adds adegree of complexity to the processing capability of manufactures toprovide a product that tears at least as well as a currently marketedproduct having a straight line of weakness. Further, imparting a shapedline of weakness in the product can lead to unequal perforations and/orinconsistency in tearing.

Accordingly, there is a continuing unmet need for an improvedperforating apparatus to manufacture a web with a shaped line ofweakness.

Accordingly, there is a continuing unmet need for an improved method tomanufacture a web with a shaped line of weakness.

Still further, there is a continuing unmet need for a sanitary tissueproduct having individual sheets separated by shaped lines of weakness,and which allows consumers to easily and readily interact with theproduct. More specifically, there is a continuing unmet need for asanitary tissue product that allows the consumer to grasp the first,exposed sheet of the product readily and easily for dispensing and use.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of thisdisclosure, and the manner of attaining them, will become more apparentand the disclosure itself will be better understood by reference to thefollowing description of non-limiting embodiments of the disclosuretaken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a perspective view of a perforating apparatus in accordancewith one non-limiting embodiment of the present disclosure;

FIG. 2 is a partial side elevation view of a perforating apparatus inaccordance with one non-limiting embodiment of the present disclosure;

FIG. 3 is a partial side elevation view of a perforating apparatus inaccordance with one non-limiting embodiment of the present disclosure;

FIG. 4 is a partial side elevation view of a perforating apparatus inaccordance with one non-limiting embodiment of the present disclosure;

FIG. 4A is a side elevation view of an anvil disposed on a cylinder inaccordance with one non-limiting embodiment of the present disclosure;

FIG. 5 is a front elevation view of an anvil disposed on a cylinder inaccordance with one non-limiting embodiment of the present disclosure;

FIG. 5A is a side elevation view of an anvil disposed on a cylinder inaccordance with one non-limiting embodiment of the present disclosure;

FIGS. 5B-G are a cross sectional view of Section 5B-G of FIG. 5 ;

FIG. 6 is a front elevation view of an anvil disposed on cylinder inaccordance with one non-limiting embodiment of the present disclosure;

FIG. 7 is a front elevation view of an anvil disposed on cylinder inaccordance with one non-limiting embodiment of the present disclosure;

FIG. 8 is a plan view of a web in position to be perforated by aperforating apparatus in accordance with one non-limiting embodiment ofthe present disclosure;

FIG. 9 is a plan view of a web in position to be perforated by aperforating apparatus in accordance with one non-limiting embodiment ofthe present disclosure;

FIGS. 10-10R are schematic representations showing the progression of aweb being perforated in accordance with one non-limiting embodiment ofthe present disclosure;

FIG. 11 is a perspective view of a perforating apparatus in accordancewith one non-limiting embodiment of the present disclosure;

FIG. 12 is a schematic representation of a notched anvil in accordancewith one non-limiting embodiment of the present disclosure;

FIG. 13 is a perspective view of a perforating apparatus in accordancewith one non-limiting embodiment of the present disclosure;

FIG. 14 is a partial side elevation view of a perforating apparatus inaccordance with one non-limiting embodiment of the present disclosure;

FIG. 15 is a partial side elevation view of a perforating apparatus inaccordance with one non-limiting embodiment of the present disclosure;

FIG. 16 is a front elevation view of a blade disposed on a support inaccordance with one non-limiting embodiment of the present disclosure;

FIG. 17 is a cross sectional view of Section 17-17 of FIG. 16 ;

FIG. 18 is a perspective schematic representation of a perforatingapparatus in accordance with one non-limiting embodiment of the presentdisclosure;

FIG. 19 is a schematic representation of a notched blade disposed on asupport and a shaped anvil disposed in a cylinder in accordance with onenon-limiting embodiment of the present disclosure;

FIG. 20 is a schematic representation of a portion of an anvilindicating perforating length or non-perforating length to determine thetooth length or recessed portion length in accordance with onenon-limiting embodiment of the present disclosure;

FIG. 21 is a schematic representation of a notched blade disposed on asupport and a shaped anvil disposed in a cylinder in accordance with onenon-limiting embodiment of the present disclosure;

FIG. 22 is a perspective view of a web in accordance with onenon-limiting embodiment of the present disclosure; and

FIGS. 23A-Q are schematic representations of the shape of a line ofweakness in accordance with one non-limiting embodiment of the presentdisclosure.

DETAILED DESCRIPTION

Various non-limiting embodiments of the present disclosure will now bedescribed to provide an overall understanding of the principles of thestructure, function, manufacture, and use of a web comprising a shapedline of weakness. The features illustrated or described in connectionwith one non-limiting embodiment can be combined with the features ofother non-limiting embodiments. Such modifications and variations areintended to be included within the scope of this disclosure.

“Fibrous structure” as used herein means a structure that comprises oneor more fibrous elements. In one example, a fibrous structure accordingto the present disclosure means an association of fibrous elements thattogether form a structure capable of performing a function. Anonlimiting example of a fibrous structure of the present disclosure isan absorbent paper product, which can be a sanitary tissue product suchas a paper towel, bath tissue, or other rolled, absorbent paper product.

Non-limiting examples of processes for making fibrous structures includeknown wet-laid papermaking processes, air-laid papermaking processes,and wet, solution, and dry filament spinning processes, for examplemeltblowing and spunbonding spinning processes, that are typicallyreferred to as nonwoven processes. Such processes can comprise the stepsof preparing a fiber composition in the form of a suspension in amedium, either wet, more specifically aqueous medium, or dry, morespecifically gaseous, i.e. with air as medium. The aqueous medium usedfor wet-laid processes is oftentimes referred to as fiber slurry. Thefibrous suspension is then used to deposit a plurality of fibers onto aforming wire or belt such that an embryonic fibrous structure is formed,after which drying and/or bonding the fibers together results in afibrous structure. Further processing the fibrous structure can becarried out such that a finished fibrous structure is formed. Forexample, in typical papermaking processes, the finished fibrousstructure is the fibrous structure that is wound on the reel at the endof papermaking and can subsequently be converted into a finished product(e.g., a sanitary tissue product).

“Fibrous element” as used herein means an elongate particulate having alength greatly exceeding its average diameter, i.e. a length to averagediameter ratio of at least about 10. A fibrous element may be a filamentor a fiber. In one example, the fibrous element is a single fibrouselement rather than a yarn comprising a plurality of fibrous elements.

The fibrous elements of the present disclosure may be spun from polymermelt compositions via suitable spinning operations, such as meltblowingand/or spunbonding and/or they may be obtained from natural sources suchas vegetative sources, for example trees.

The fibrous elements of the present disclosure may be monocomponentand/or multicomponent. For example, the fibrous elements may comprisebicomponent fibers and/or filaments. The bicomponent fibers and/orfilaments may be in any form, such as side-by-side, core and sheath,islands-in-the-sea and the like.

“Filament” as used herein means an elongate particulate as describedabove that exhibits a length of greater than or equal to 5.08 cm (2 in.)and/or greater than or equal to 7.62 cm (3 in.) and/or greater than orequal to 10.16 cm (4 in.) and/or greater than or equal to 15.24 cm (6in.).

Filaments are typically considered continuous or substantiallycontinuous in nature. Filaments are relatively longer than fibers.Non-limiting examples of filaments include meltblown and/or spunbondfilaments. Non-limiting examples of polymers that can be spun intofilaments include natural polymers, such as starch, starch derivatives,cellulose, such as rayon and/or lyocell, and cellulose derivatives,hemicellulose, hemicellulose derivatives, and synthetic polymersincluding, but not limited to polyvinyl alcohol, thermoplastic polymer,such as polyesters, nylons, polyolefins such as polypropylene filaments,polyethylene filaments, and biodegradable thermoplastic fibers such aspolylactic acid filaments, polyhydroxyalkanoate filaments,polyesteramide filaments and polycaprolactone filaments.

“Fiber” as used herein means an elongate particulate as described abovethat exhibits a length of less than 5.08 cm (2 in.) and/or less than3.81 cm (1.5 in.) and/or less than 2.54 cm (1 in.). A fiber can beelongate physical structure having an apparent length greatly exceedingits apparent diameter (i.e., a length to diameter ratio of at leastabout 10.) Fibers having a non-circular cross-section and/or tubularshape are common; the “diameter” in this case can be considered to bethe diameter of a circle having a cross-sectional area equal to thecross-sectional area of the fiber.

Fibers are typically considered discontinuous in nature. Non-limitingexamples of fibers include pulp fibers, such as wood pulp fibers, andsynthetic staple fibers such as polypropylene, polyethylene, polyester,copolymers thereof, rayon, glass fibers and polyvinyl alcohol fibers.

Staple fibers may be produced by spinning a filament tow and thencutting the tow into segments of less than 5.08 cm (2 in.) thusproducing fibers.

In one example of the present disclosure, a fiber may be a naturallyoccurring fiber, which means it is obtained from a naturally occurringsource, such as a vegetative source, for example a tree and/or otherplant. Such fibers are typically used in papermaking and are oftentimesreferred to as papermaking fibers. Papermaking fibers useful in thepresent disclosure include cellulosic fibers commonly known as wood pulpfibers. Applicable wood pulps include chemical pulps, such as Kraft,sulfite, and sulfate pulps, as well as mechanical pulps including, forexample, groundwood, thermomechanical pulp and chemically modifiedthermomechanical pulp. Chemical pulps, however, may be preferred sincethey impart a superior tactile sense of softness to fibrous structuresmade therefrom. Pulps derived from both deciduous trees (hereinafter,also referred to as “hardwood”) and coniferous trees (hereinafter, alsoreferred to as “softwood”) may be utilized. The hardwood and softwoodfibers can be blended, or alternatively, can be deposited in layers toprovide a stratified web. Also applicable to the present disclosure arefibers derived from recycled paper, which may contain any or all of theabove categories of fibers as well as other non-fibrous polymers such asfillers, softening agents, wet and dry strength agents, and adhesivesused to facilitate the original papermaking.

In addition to the various wood pulp fibers, other cellulosic fiberssuch as cotton linters, rayon, lyocell, and bagasse fibers can be usedin the fibrous structures of the present disclosure.

“Sanitary tissue product” as used herein means one or more finishedfibrous structures, that is useful as a wiping implement forpost-urinary and post-bowel movement cleaning (e.g., toilet tissue, alsoreferred to as bath tissue, and wet wipes), for otorhinolaryngologicaldischarges (e.g., facial tissue), and multi-functional absorbent andcleaning and drying uses (e.g., paper towels, shop towels). The sanitarytissue products can be embossed or not embossed and creped or uncreped.

In one example, sanitary tissue products rolled about a fibrous core ofthe present disclosure can have a basis weight between about 10 g/m² toabout 160 g/m² or from about 20 g/m² to about 150 g/m² or from about 35g/m² to about 120 g/m² or from about 55 to 100 g/m², specificallyreciting all 0.1 g/m² increments within the recited ranges. In addition,the sanitary tissue products can have a basis weight between about 40g/m² to about 140 g/m² and/or from about 50 g/m² to about 120 g/m²and/or from about 55 g/m² to about 105 g/m² and/or from about 60 to 100g/m², specifically reciting all 0.1 g/m² increments within the recitedranges. Other basis weights for other materials, such as wrapping paperand aluminum foil, are also within the scope of the present disclosure.

“Basis Weight” as used herein is the weight per unit area of a samplereported in lbs/3000 ft² or g/m². Basis weight can be measured bypreparing one or more samples to create a total area (i.e., flat, in thematerial's non-cylindrical form) of at least 100 in² (accurate to +/−0.1in²) and weighing the sample(s) on a top loading calibrated balance witha resolution of 0.001 g or smaller. The balance is protected from airdrafts and other disturbances using a draft shield. Weights are recordedwhen the readings on the balance become constant. The total weight (lbsor g) is calculated and the total area of the samples (ft² or m²) ismeasured. The basis weight in units of lbs/3,000 ft² is calculated bydividing the total weight (lbs) by the total area of the samples (ft²)and multiplying by 3000. The basis weight in units of g/m² is calculatedby dividing the total weight (g) by the total area of the samples (m²).

“Density” as used herein is calculated as the quotient of the BasisWeight expressed in grams per square meter divided by the Caliperexpressed in microns. The resulting Density is expressed as grams percubic centimeter (g/cm³ or g/cc). Sanitary tissue products of thepresent disclosure can have a density of greater than about 0.05 g/cm³and/or greater than 0.06 g/cm³ and/or greater than 0.07 g/cm³ and/orless than 0.10 g/cm³ and/or less than 0.09 g/cm³ and/or less than 0.08g/cm³ and/or less than 0.60 g/cm³ and/or less than 0.30 g/cm³ and/orless than 0.20 g/cm³ and/or less than 0.15 g/cm³ and/or less than 0.10g/cm³ and/or less than 0.07 g/cm³ and/or less than 0.05 g/cm³ and/orfrom about 0.01 g/cm³ to about 0.20 g/cm³ and/or from about 0.02 g/cm³to about 0.15 g/cm³ and/or from about 0.02 g/cm³ to about 0.10 g/cm³.

“Ply” as used herein means an individual, integral fibrous structure.

“Plies” as used herein means two or more individual, integral fibrousstructures disposed in a substantially contiguous, face-to-facerelationship with one another, forming a multi-ply fibrous structureand/or multi-ply sanitary tissue product. It is also contemplated thatan individual, integral fibrous structure can effectively form amulti-ply fibrous structure, for example, by being folded on itself.

“Rolled product(s)” as used herein include plastics, fibrous structures,paper, sanitary tissue products, paperboard, polymeric materials,aluminum foils, and/or films that are in the form of a web and can bewound about a core. For example, the sanitary tissue product can beconvolutedly wound upon itself about a core or without a core to form asanitary tissue product roll or can be in the form of discrete sheets,as is commonly known for toilet tissue and paper towels.

“Machine Direction,” MD, as used herein is the direction of manufacturefor a perforated web. The machine direction can be the direction inwhich a web is fed through a perforating apparatus that can comprise arotating cylinder and support, as discussed below in one embodiment. Themachine direction can be the direction in which web travels as it passesthrough a blade and an anvil of a perforating apparatus.

“Cross Machine Direction,” CD as used herein is the directionsubstantially perpendicular to the machine direction. The cross machinedirection can be substantially perpendicular to the direction in which aweb is fed through a cylinder and lower support in one embodiment. Thecross machine direction can be the direction substantially perpendicularto the direction in which web travels as it passes through a blade andan anvil.

Referring to FIG. 1 , a perforating apparatus 10 is shown for forming ashaped line of weakness 21 comprising one or more perforations 22 on aweb 14. The perforating apparatus 10 comprises a cylinder 12 and asupport 18. The cylinder 12 can be suspended between one or more braces28 that serve to hold cylinder 12 in operative position. The cylinder 12has a longitudinal cylinder axis 24 about which the cylinder 12 isrotatable. The cylinder 12 can have a substantially circular shapedcross-section or oval-like shaped cross-section or any other shapedcross-section that can rotate about an axis and operatively engage asupport 18. The cylinder 12 can comprise an outer surface 30 positionedradially outward from and substantially surrounding the longitudinalcylinder axis 24.

The cylinder 12 can comprise an anvil 16. In one example embodiment, theanvil 16 can be disposed on the outer surface 30 of the cylinder 12. Inanother example embodiment, the anvil 16 can be disposed on an anvilinsert 29 that can be removably attached to the cylinder 12. The anvilinsert 29 can be magnetically attached to the outer surface 30 of thecylinder 12. In another embodiment, the anvil insert 29 can bechemically attached, such as by glue, or mechanically attached, such asby clamping, bolting, or otherwise joining to the outer surface 30 ofthe cylinder 12. Opposite the cylinder 12, the support 18 can comprise ablade 20. The blade 20 can be disposed on the support 18. By “disposed”is meant the blade can be attached, removeably attached, clamped,bolted, or otherwise held by the support 18 in a stable operativeposition with respect to the cylinder 12.

In another example embodiment, the support 18 can comprise a bladeholder 27. The blade 20 can be disposed on the blade holder 27 in such amanner as to maintain sufficient stability when in contacting engagementwith the anvil 16. Further, a clamp 31, shown in FIG. 2 , can bedisposed on the blade holder 27 and partially surround the blade 20. Theclamp 31 can be designed generally as indicated in FIG. 2 with the bladebeing held between two parts of the clamp that can each flex relative tothe other. In this manner the clamp 31 can removably hold the blade 20such that the blade 20 can deflect when it contacts the anvil 16. Thisdeflection and the inherent flexibility of the blade 20 allows forimproved perforation reliability by being more forgiving to slightdifferences in machine tolerances. Thus, the support 18 serves to holdthe blade holder 27, which can include a clamp 31, and thus the blade20, in a relatively stable orientation during operation.

The cylinder 12 is moveable such that the cylinder 12 can operativelyengage with the support 18. Operative engagement means the support 18can be arranged in relationship to the cylinder 12 such that the blade20 can make contact with the anvil 16 as it rotates past the blade 20;the contact sufficient to make one or more perforations 22 in a web 14.In one embodiment, the contact between the anvil 16 and the blade 20 isa shearing action. Thus, in one embodiment, the perforating apparatuscan be a shear-cutting device. The blade 20 can be disposed on thesupport 18 so as to cooperate in contacting relationship with the anvil20 disposed on the cylinder 12 to impart a line of weakness 21comprising one or more perforations 22 and one or more bond areas 23 inthe web 14. The bond areas 23 are the portion of the web between twoadjacent perforations. The inventors found a unique and surprisingresult from shaping the element disposed on the rotating cylinder 12. Inone embodiment, the shaped element can comprise the anvil 16. Theresulting perforation on the sheet takes on the same or a similar shapeas the shaped rotating element, which, in one embodiment is a shapedanvil 16. The same result does not occur if the shape is not on therotating roll.

As previously stated, the line of weakness 21 comprising perforations 22and bond areas 23 can be the shape of the anvil 16. The characteristicsof the one or more perforations 22 and bond areas 23 can be due, inpart, to the interaction point 26. Referring to FIGS. 1-4 , theinteraction point 26 is the point where contact occurs between the anvil16 and blade 20. The characteristics of the perforations 22 can be aresult of the amount of overlap between the blade 20 and anvil 16 andhow the blade 20 and the anvil 16 cooperate in contacting relationship.For example, the blade 20 against the anvil 16 can result in a shearingaction that imparts certain characteristics to the perforations 22. Inone embodiment, the interaction point 26 can be adjusted by moving thesupport 18 and/or the cylinder 12. In an alternative embodiment, theinteraction point 26 can be adjusted by moving the anvil insert 29 onwhich the anvil 16 is disposed and/or the blade holder 27 and/or theclamp 31 on which the blade 20 can be disposed. Thus, the interactionpoint 26 can be increased or decreased, which alters the characteristicsof the resulting line of weakness 21 imparted to the web 14 and, thus,the characteristics of each perforation 22 and bond area 23. Theinteraction point 26, the overlap of the blade 20 operatively engagingthe anvil 16, can be from about 0.0001 inches to about 0.01 inchesand/or from about 0.0005 inches to about 0.009 inches, including all1/10000 of an inch therebetween. For example, an overlap of 0.0006inches would be covered in the above range. By increasing the overlapbetween the blade 20 and the anvil 16, the perforations 22 generallybecome more pronounced, more visible, crisper and longer. By decreasingthe overlap between the blade 20 and the anvil 16, the perforations 22generally become less pronounced, less visible, shorter, and the bond 23becomes wider and thus stronger. Thus, the interaction point 26 can bean important design consideration to create a line of weakness 21comprising a plurality of perforations 22 and bond areas 23 betweenadjacent perforations 22 that allow the sheets to be held togetherduring the manufacturing process and easily separated by consumersduring use.

As stated above, the anvil 16 and the blade 20 cooperate in contactingrelationship. Generally, the anvil 16 can be a substantially hardenedsteel surface such that there is little to no deflection of the anvil 16as it cooperates with the blade 20. By contrast, as the blade 20cooperates with the anvil 16, the blade 20 can deflect against the anvil16 creating a line of weakness 21 in the web 14. In one embodiment, theclamp 31 can be designed such that it allows the blade 20 to flex as itinteracts with the anvil 16. More specifically, as shown in FIG. 2 , theclamp 31 can be designed with an opening that allows at least a portionof the clamp 31 (for example, the lower portion shown in FIG. 2 ) tomove as the blade 20 interacts with the anvil 16. Alternatively, theclamp 31 can be designed such that the blade 20 remains substantiallyrigid as it interacts with the anvil 16. The rigidity/flexibility of theblade 20 against the anvil 16 can also alter the characteristics of theresulting line of weakness 21 imparted to the web 14, and, thus, thecharacteristics of each perforation 22 and bond area 23. The line ofweakness 21 can be imparted to the web 14 in the cross machine directionCD as the web 14 proceeds through the perforating apparatus 10 in themachine direction MD.

Referring to FIGS. 1-3 , the support 18 can be positioned in a number oforientations relative to the cylinder 12 and still result in the anvil16 operatively engaging the blade 20. As shown in FIG. 1 , the support18 can be positioned below the cylinder 12 as the web 14 is perforated.In another embodiment, as shown in FIG. 2 , the cylinder 12 can bepositioned below the support 18. In yet another embodiment, the cylinder12 and the support 18 can be positioned side by side, as shown in FIG. 3. The support 18 and cylinder 12 can be placed in any position relativeto one another that allows for the blade 20 and anvil 16 to cooperate incontacting relationship to form a line of weakness 21 across the widthof web 14. Stated another way, the support 18 and the cylinder 12 can beplaced in any position relative to one another such that an interactionpoint 26 exists between the blade 20 and the anvil 16 sufficient to forma line of weakness 21 across the width of web 14. Alternatively or inaddition to the adjustment of the support 18 and the cylinder 12, theanvil insert 29 and/or the blade holder 27 and/or the clamp 31 can beadjusted with respect to one another such that an interaction point 26exists between the blade 20 and the anvil 16 sufficient to form a lineof weakness 21 across the web 14. In one embodiment, for example, theblade 20 can be adjusted in the clamp 31 such that the blade 20 forms aninteraction point 26 with each anvil 16 disposed about the cylinder 12.

The cylinder 12 can be a solid or substantially hollow cylindricalshaped device having a hardened outer surface 30. The cylinder 12 can beformed of metal, such as steel, or some other material known to thoseskilled in the art to be suitable for use in forming perforations in aweb. The outer surface 30 can be substantially smooth apart from orincluding the anvil 16. The cylinder has a length L, as shown in FIG. 1, and a diameter D, as shown in FIG. 4 . The diameter D and the Length Lcan be sized to handle the length and width of a web 14 that can passover the outer surface 30 of cylinder 12. For example, in oneembodiment, a web can comprise a finished fibrous structure having asubstantially continuous length, a width of about 10 inches to about 125inches, and a thickness of about 0.009 inches to about 0.070 inches.Alternatively, the length L of the cylinder 12 can be sized to besubstantially the same length as the support 18, such that the blade 20can operatively engage the anvil 16 along its full length. In oneembodiment, the cylinder 12 can have a diameter D of about 5 inches toabout 20 inches and/or about 8 inches to about 15 inches. The cylinder12 can have a length L of about 10 inches to about 150 inches.

The cylinder 12 can comprise at least one anvil 16 disposed on the outersurface 30, as illustrated in FIGS. 1-5 . The anvil 16 can protrudeabove the outer surface 30, that is extend radially outward from thesurface 30. The anvil 16 can be made from one or more of tool steel,carbon steel, aluminum, ceramic, hard plastic or other suitablematerial. The anvil 16 can be coated with materials to enhance itsstrength and wear resistance (also referred to as machine life). Forexample, in one embodiment, the anvil 16 can be subject toplasma-enhanced chemical vapor deposition to deposit a thin film ofmaterial on the surface of the anvil 16. Materials that can be used toprolong the machine life of the anvil 16 can include titanium oxide andceramic coatings. The anvil 16 can be fixed to or removably attached tothe outer surface 30. For example, in one embodiment, the outer surface30 can be machined to form an anvil 16 by effectively removing materialfrom the outer surface 30. In an alternative embodiment, an anvil 16 canbe a separate member that can be inserted and removably attached to thecylinder 12, as shown in FIGS. 2, 3, and 5 . The anvil 16 can bedisposed on an anvil insert 29, which can be removably attached to theouter surface 30 of the cylinder 12. In one embodiment, the anvil 16 canbe machined from the surface of the anvil insert 29. In alternativeembodiment, the anvil 16 can be removably attached mechanically, such asby bolting, clamping, or screwing, or chemically, such as by adhering tothe anvil insert 29.

A removably attached anvil 16 can aid in quickly changing out dull,worn, and/or damaged parts. Further, a removably attached anvil 16 canallow for easily changing from a straight perforation system to a shapedperforation system. In one example embodiment, the cylinder 12 cancomprise an anvil 16 comprised of one or more anvil segments 17positioned end-to-end along the length L of the cylinder 12, as shown inFIG. 5 . Each anvil segment 17 can have a length sufficient forinteracting with the blade 20 and/or easily removing segments forreplacement. Thus, each individual anvil segment 17 can be removed andreplaced independent of another anvil segments 17 disposed on thecylinder 12. Each anvil segment 17 can be adjusted on the outer surfaceof the cylinder 12 to change how the anvil 16 contacts the blade 20 andperforates the web 14. For example, a series of adjustment screws may beused to independently raise or lower the removably attached individualanvil segments 17 to facilitate an overall anvil 16 adjustment. Further,each anvil segment 17 can be positioned independent of another anvilsegment 17 such that the blade 20 interacts differently with thedifferent sections creating a line of weakness 21 having a plurality ofperforations 22 and bond areas 23 with different characteristics, suchas strength and/or size.

In addition to one or more anvil segments 17 being disposed end to endto extend along the length L of the cylinder 12, one or more anvils 16(each of which can comprise individual anvil segments 17 or a continuoussingle-piece anvil) can be spaced radially about the outer surface 30,as shown in FIGS. 2-4 . The one or more anvils 16 can be spaced radiallyabout the outer surface 30 such that each line of weakness 21 on the web14 is produced at some desired distance from one another, which canresult in a desired sheet length. For example, in one embodiment, acylinder 12 having a diameter D of about 12 inches can comprise twoanvils 16 spaced equidistant to one another around the outer surface 30of the cylinder 12. A web 14 can be fed through a perforating apparatus10 comprising the cylinder 12 such that the machine direction MD of theweb is substantially perpendicular to the longitudinal cylinder axis 24of the cylinder 12. In another embodiment, a web 14 can be fed through aperforating apparatus 10 comprising the cylinder 12 such that themachine direction MD of the web is at an angle to the longitudinalcylinder axis 24 of the cylinder 12, which is disclosed in more detailbelow.

Successive lines of weakness 21 imparted to the web 14 can be spaced ata distance equal to about the circumference of the cylinder 12 dividedby the number of anvils 16 spaced equidistant to one another. Statedanother way, the spacing of lines of weakness 21 on the web 14 can beabout equal to the spacing between each anvil 16 disposed on the outersurface 30 of the cylinder 12. For example, a cylinder 12 comprisingnine rows of anvils 16 disposed radially about the outer surface 30 anda desired sheet length of about four inches, the cylinder 12 can have adiameter of about 11.5 inches and a circumference of about 36 inches. Inan alternative example embodiment, the distance between one or moreanvils 16 disposed about the outer surface 30 can be unequal and, thus,the line of weakness 21 on the web 14 can also spaced at unequaldistances one from another, being about equal to the distance betweenadjacent anvils 16 disposed about the cylinder 12. One of ordinary skillin the art would understand that for the line of weakness 21 on the web14 to be equal to the distance between the one or more anvils 16, thespeed of the web 14 would substantially match the rotational speed ofthe cylinder 12 and the longitudinal cylinder axis 24 would besubstantially perpendicular to the machine direction of the web 14.Likewise, one of ordinary skill in the art would understand that byover-speeding or under-speeding the web 14, the MD spacing between thelines of weakness 21 can be varied with respect to the spacing betweenanvils 16 on cylinder 12. In another embodiment, the cylinder 12 can beboth over-sped and under-sped to produce variable sheet lengths in theweb 14. Thus, the cylinder can be run at a constant over-speed, aconstant under-speed or variable speeds, both over-speed andunder-speed.

The anvil 16 can have any substantially continuous, non-linear shape(also referred to as a curvilinear shape), for example, a sinusoidalshape or saw-tooth shape, as illustrated in FIGS. 1, 5, 6, 7, and 23A-Q.The continuous line segment shape of the anvil 16 is dependent on thedesired shape of the line of weakness 21 in the web 14.

As illustrated in FIGS. 5A-G, the continuous line segment shaped anvil16 can have a shaped cross section. The anvil 16 can be any non-linearshape that allows the anvil 16 to cooperate in contacting relationshipwith the blade 20 to impart a line of weakness 21 to a web 14. In oneembodiment, the anvil 16 can have a substantially square or rectangularcross section. In another example embodiment, the anvil 16 can have asubstantially flat top, as shown in FIGS. 5D and 5E. Similarly, theanvil 16 can have a substantially concave or convex cross section. Stillin another embodiment, the anvil 16 can have a substantially triangularcross section. Other cross sections that would allow for the anvil 16 tobe in contacting relationship with the blade 20 would be readilydiscernible to one skilled in the art. Further, the anvil 16 can bedesigned such that the stresses are minimized at the root 72. Forexample, in one embodiment, the root 72 can be radiused with a radius ofcurvature that minimizes stress concentrations. The radius of curvaturecan range from 0.010 inches to about 1 inch.

Referring to FIG. 5 , in one embodiment, the anvil 16 can be acontinuous line segment shape that is substantially parallel to or atsome angle to (discussed more fully below) the longitudinal cylinderaxis 24. The continuous, non-linear shape of the anvil 16 can comprisean amplitude 32, which is the distance measured between a highest pointand an adjacent lowest point, opposite the highest point, of a shapedanvil 16 along the outer surface 30 of the cylinder 12. The amplitude 32can vary between adjacent high points and low points. One or moreamplitudes 32 present on the outer surface 30 of the cylinder 12 can besubstantially the same or different. Similarly, the anvil 16 cancomprise a wavelength 34, which is the distance measured betweenadjacent crests or adjacent troughs in a repeating portion of thecontinuous line segment shaped anvil along the outer surface 30 of thecylinder 12. For example, as shown in FIG. 5 , the anvil 16 repeats at afirst low point and a consecutive low point that defines a distancetherebetween being the wavelength 34. In one embodiment, the anvil 16can comprise less than one repeating portion and, thus, the number ofwavelengths 34 would be less than one. In another embodiment, the anvil16 can comprise more than one wavelength 34. More specifically, forexample, as shown in FIG. 5 , the anvil 16 can comprise about twowavelengths 34 labeled A and B. The distance of wavelength A can begreater than, less than, or equal to the distance of wavelength B.

The wavelength 34 and amplitude 32 can be selected to minimize or avoidchatter in the perforating apparatus 10. Chatter is the vibrationimparted to the perforating apparatus 10 as the blade 20 cooperates incontacting relationship with the anvil 16 at operating speeds. Chattercan be avoided or reduced by minimizing the number of simultaneousinteraction points 26 between the anvil 16 and the blade 20. Thecontinuous line segment shape of the anvil 16 can allow for a reductionin the number of interaction points 26 between the anvil 16 and theblade 20. For example, in one embodiment, the anvil 16 can comprise awave-form shape, as shown in FIG. 5 , that is substantially parallel tothe longitudinal cylinder axis 24. The shape of the anvil 16 results ina certain number of interaction points 26 as the straight blade 20passes over the anvil 16. For example, as the blade 20 passing over theanvil 20, as shown in FIG. 5 , the blade 20 overlaps the anvil 16creating interaction points 26 of at most about five points and at leastabout two points at a given moment in time. Therefore, changing theamplitude 32 and wavelength 34 of an anvil 16 that is substantiallyparallel to the longitudinal cylinder axis 24 will change the number ofinteraction points 26 between the anvil 16 and blade 20 at a givenmoment in time.

One of ordinary skill in the art would understand that the anvil 16 canbe designed to impart a desired shape of a line of weakness 21 in theabsorbent tissue product. In one embodiment, the anvil 16 can bedesigned such that the line of weakness 21 on a web 14, such asabsorbent sheet product (also referred to as a sanitary tissue product),can have a wavelength 34 from about 10% of the sheet width to about 200%of the sheet width and an amplitude 32 of less than about 50% of thedistance between adjacent lines of weakness 21. For example, in oneembodiment, the absorbent sheet product can have a width of about 3.5inches and the distance of the wavelength 34 can be about 50% of thesheet width, which is about 1.75 inches. Thus, the line of weakness 21imparted to the absorbent sheet product can have at least one wavelength34. For example, an absorbent sheet product having a distance betweenadjacent lines of weakness 21 of about 4 inches can comprise a line ofweakness 21 having an amplitude 32 of about 2 inches.

Still further, chatter can be reduced by nesting one or more anvils 16disposed on the outer surface 30 of the cylinder 12 (not shown). Bynesting one or more anvils 16 the blade 20 can remain in constantcontact with the anvil 16. Having the blade 20 in constant engagementwith the anvil 16 can allow the cylinder 12 to remain balanced andstabilized and, thus, reduce chatter in the perforating apparatus 10.Additionally, other ways to reduce chatter include, for example,positioning the anvil 16 so that it is helixed about the cylinder 12. Asillustrated in FIGS. 6 and 7 , the anvil 16 can be mounted at an anglewith respect to axis 24, such that it extends in a helical orientationon the outside surface 30 of the cylinder 12. The anvil 16 can be at anangle α to the longitudinal cylinder axis 24 of from greater than 0degrees to about 45 degrees and/or from about 2 degrees to about 20degrees and/or from about 4 degrees to about 8 degrees. When used with ablade 20 positioned substantially parallel to cylinder axis 24, thehelically mounted anvil 16 can reduce the number of simultaneousinteraction points 26 at a given period in time between the anvil 16 andthe blade 20. In one embodiment, the helically mounted shaped anvil 16results in cooperation between the anvil 16 and blade 20 such that thereless simultaneous interaction points 26 than a similar non-helixed anvil16.

In one example embodiment, each perforation 22 in the line of weakness21 can be formed one at a time as the anvil 16 interacts with thestraight blade 20 at a single location at a given moment in time. Byhelically mounting the anvil 16, the blade 20 operatively engages theanvil 16 at minimal interaction points 26. For example, the blade 20 canengage the helical anvil 16 such that the perforations 22 are created bya consecutive series of minimized interaction points 26 across theentire web 14 in a zipper-like manner. Further, helically mounting theanvil 16 can allow the anvil 16 to be in constant engagement with theblade 20. Stated another way, by helically mounting one or more anvils16 about the outer surface 30 of by the cylinder 12 a portion or pointof the anvil 16 can always be in contact with a portion or point of theblade 20, as illustrated in FIG. 8 . In one embodiment, the blade 20 canhave almost traversed one anvil 16 such that substantially the entireline of weakness 21 has been imparted to the web 14 while almostsimultaneously encountering a subsequent anvil 16, such that thecreation of the line of weakness 21 in the web 14 is just beginning.Having the blade 20 in constant engagement with the anvil 16 can allowthe cylinder 12 to remain balanced and stabilized and, thus, reducechatter in the perforating apparatus 10.

However, helically mounting the anvil 16 about the cylinder 12 andrunning the web 14 at matched speed to the cylinder 12, can result inthe line of weakness 21 being at an angle to the CD, as illustrated inFIG. 8 . The angle of the helixed anvil 16 to the longitudinal cylinderaxis 24, angle α, can be substantially the same angle of the line ofweakness 21 to the cross machine direction, CD. To compensate for theangle in the line of weakness 21, the web 14 can be run at a speedslower than the cylinder 12. By running the web 14 slower than therotating cylinder 12, the web 14 can move a lesser distance before eachsubsequent perforation 22 is imparted to the web 14. However, there arelimitations as to how fast or how slow the cylinder 12 can be sped withrespect to the web 14.

The perforating apparatus 10 can also be skewed with respect to the web14 to correct for an angle in the line of weakness 21 with respect tothe CD, as shown in FIG. 9 . Thus, the angle of the perforatingapparatus 10 with respect to the web 14 allows a line of weakness 21that is substantially parallel to the CD to be imparted to the web 14despite the helically mounted anvil 12. More specifically, as disclosedabove, the anvil 16 can be helixed at some angle α with respect to thelongitudinal cylinder axis 24. The cylinder 12 comprising the anvil 16and the support 18 comprising the blade 20 can be skewed by some angle θwith respect to the CD of the web 14. The cylinder 12 and the blade 20are skewed relative to one another such that the longitudinal cylinderaxis 24 is substantially parallel to the blade 20. The angle θ can beequal to about the angle α. The angle θ can be greater than or less thanabout the angle α. In one example embodiment, the angle θ can be from 0degrees to about 45 degrees and/or from about 2 degrees to about 20degrees and/or from about 4 degrees to about 8 degrees.

Where the web 14 is skewed with respect to the perforating apparatus 10,the web 14 may experience a force vector that drives the web 14 off of adesired path as the web 14 is exiting the perforating apparatus 10. Inother words, the web 14 may travel at an angle out of the perforatingapparatus 10 as opposed to following a desirable straight line path 15.Wrapping the web 14 about one or more idlers may reduce the web 14likelihood to travel at an undesirable angle. In one nonlimitingexample, an idler is placed upstream of the cylinder 12 and/or upstreamof blade 20. In another nonlimiting example, an idler is placeddownstream of the cylinder 12 and/or downstream of the blade 20. Theidler may be wrapped with sandpaper, such as 60-grit sandpaper or120-grit sandpaper. In another embodiment, the idler can be providedwith a means to increase the coefficient of friction on its surface.

Further to the above, the characteristics of the line of weakness 21 onthe web 14 can be changed by over-speeding or under-speeding the web 14and/or the cylinder 12 comprising the shaped anvil 16. As illustrated inFIG. 10 , the shape of the line of weakness 21 on the web 14 can changewhen over-speeding the web 14 with respect to the rotating cylinder 12,which is also referred to as under-speeding the rotating cylinder 12with respect to the speed of the web 12. When the web 14 moves at afaster speed than the rotating cylinder 12, the line of weakness 21 canbecome distorted as compared to the shape of the anvil 16. For example,a web 14 moving at a faster speed than the cylinder 12 through theinteraction point 26 can have an increased amplitude 32 as shown in FIG.10R. FIGS. 10A-10R illustrate how perforations 22 can be imparted to aweb 14 running at an over-speed. Thus, FIG. 10A depicts the firstinteraction point 26 of the anvil 16 to the blade 20 creating aperforation 22, FIGS. 10B through 10Q depict the progression of the web14 and the perforations 22 imparted to the web 14, and FIG. 10R showsthe final interaction point 26 of the anvil 16 and the blade 20 creatingthe final perforation 22 in the web 14.

One of ordinary skill in the art would understand that by over-speedingthe cylinder 12 with respect to the web 14, the line of weakness 21would again become distorted as compared to the shape of the anvil 16.For example, by over-speeding the cylinder 12 with respect to the web14, the amplitude 32 of the line of weakness 21 will become shorter thanthe amplitude of the shaped anvil 16. Thus, the design of the shapedanvil 16 disposed on the cylinder 12 should be taken into considerationto produce the desired line of weakness 21 when over-speeding orunder-speeding the web 14 or the cylinder 12.

Further, the web 14 can be perforated while under tension in the machinedirection MD. The tension on the web 14 in the MD results in the web 14becoming elongated in the MD and narrower in the cross machine directionCD. This phenomena of elongation in the MD and narrowing in the CD isreferred to as neck-down. For a web 14 under tension in the MD andnarrowed in the CD as it is passed through the perforating apparatus 10,the line of weakness 21 imparted to the web 14 on the final rolledabsorbent product can be different than the profile of the shaped anvil16 disposed on the rotating cylinder 12 and/or the shaped line ofweakness 21 imparted to the web 14 just after passing through theperforating apparatus 10. Once the web 14 is wound onto a final rolledabsorbent product and is no longer under the same tension as whenperforated, the web 14 can return to its original, non-tensioneddimensions. More specifically, the web 14 in the MD can contract backand the web 14 in the CD can become wider. The shaped line of weakness21 imparted to the web 14 undergoes a similar transformation once thetension in the web 14 is lessened or removed. In one example embodiment,a curvilinear line of weakness 21 on the final rolled absorbent product,which was perforated under tension and is now no longer under tension,can have an amplitude that is less than the amplitude imparted when theweb 14 was under tension just after passing through the perforatingapparatus 10, and an increased wavelength distance as compared to thedistance of the wavelength of the web 14 under tension after justpassing through the perforating apparatus 10. Thus, the shape of theanvil 16 disposed on the rotating cylinder 12 can be designed to accountfor the tension, if any, in the web 14 so as to produce the desiredcurvilinear shape in the line of weakness 21 of the final rolledabsorbent product.

In yet another embodiment, the anvil 16 can be smooth-edged or notched,as shown in FIGS. 6 and 11 , respectively. As illustrated in FIGS. 11and 12 , a notched anvil 16 can comprise a plurality of teeth 36 and oneor more recessed portions 38. Each adjacent tooth can be separated by arecessed portion 38. The one or more teeth 36 and/or recessed portions38 can be machined into the anvil 16 or removably attached to the anvil16. Referring to FIG. 12 , each tooth 36 can have a length TL and aheight TH and each recessed portion 38 can have a length RL. Eachrecessed portion 38 can be separated by an adjacent tooth length TL. Thetooth height TH can be designed to obtain the desired perforationcharacteristics. In one example embodiment, the tooth height TH can befrom about 0.005 inches to about 0.500 inches, including every 0.001inches therebetween. The tooth length TL is dependent upon the desiredsize of perforation. Stated another way, the spacing of the one or moreteeth 36 and one or more recessed portions 38 determines the spacing ofeach perforation 22 and bond area 23 along the line of weakness 21.Thus, the spacing of the one or more notches 36 and one or more recessedportions 38 can be such that evenly spaced perforations 22 are producedin the web 14 despite the shape of the anvil 16. This will be discussedin greater detail below. Alternatively, the anvil 16 can comprise asmooth-edge or non-notched edge, as shown in FIG. 1 . Generally, if theanvil 16 comprises a plurality of teeth 36, the blade 20 can comprise asmooth-edge or non-notched edge, as shown in FIG. 11 . Likewise, if theanvil 16 is smooth-edged, that is contains no teeth, the blade 20 cancomprise a plurality of teeth 36.

As discussed above, the support 18, as shown in FIGS. 1 and 2 , cancomprise a support surface 40 and a blade 20 disposed thereon. Thesupport 18 can be formed from metal, such as steel or a steel alloy, orfrom some other material as would be known to those skilled in the artto be suitable as a structural support of perforating equipment. Thesupport 18 can be in a block shape, as illustrated in FIG. 2 , acylindrical shape, as illustrated in FIG. 13 , or another shape thatwould adequately support a blade 20. The support 18 can be placed in afixed, non-moveable, non-rotatable position during contactingrelationship with the anvil 16, independent of the shape of the support18. In one example embodiment, the support 18 can be a cylindrical shapeor a substantially square shape such that when one or more blades 20disposed on the outer surface wear or break, the support 18 can berotated and fixed in a position so that a new blade 20 can be placed incontacting relationship with the anvil 16. Alternatively, the support 18can be rotated and/or adjusted in and out of contacting relationshipwith the anvil 16 to easily and readily replace worn or damaged blades20.

One or more blades 20 can be disposed around the support surface 40, asshown in FIGS. 1, 14, and 15 . Having more than one blade 20 disposedabout the support surface 40 can allow for quick change out of worn ordamaged blades by indexing or rotating the support surface such that anew blade engages with the anvil 16. Additionally, having more than oneblade 20 can allow for quickly changing to different blade orientationsor configurations leading to different line of weakness 21characteristics, such as different shapes, and different individualperforations 22 characteristics, such as length, in the web 14. Forexample, the width and length of one blade 20 disposed about the supportsurface 40 can be different than the length of an adjacent blade 20disposed about the same support surface 40.

Still referring to FIGS. 14 and 15 , the blade 20 can be removablysecured to the support 18. The blade 20 can be adjusted on the support18 to be adequately positioned to engage with the anvil 16. The blade 20can be positioned substantially parallel to the longitudinal cylinderaxis 24. The blade 20 disposed on the support 18 can be substantiallyparallel to or substantially perpendicular to a support surface 40.Alternatively, the blade 20 can be at some angle β to the supportsurface 40. The angle β can be from about 20 degrees to about 160degrees and/or from about 20 degrees to about 110 degrees and/or fromabout 23 degrees to about 90 degrees and/or about 25 degrees to about 60degrees, and/or about 20 degrees to about 26 degrees, for each rangeincluding every 0.1 degree therebetween. It is believed that the lowerthe angle β, the higher the degree of flexibility when operating theapparatus 10. More specifically, the perforating apparatus 10 is lesssensitive to changes in the distance between the cylinder 12 and thesupport surface 40 when the angle β is lower. For instance, where β is35 degrees, a change in the distance between the support surface 40 andthe cylinder 12 by just a couple of thousandths of inches could resultin uneven, ripped or otherwise inadequate perforations 22. On the otherhand, where β is 21 degrees, the distance between the support surface 40and the cylinder 12 can be adjusted by thousandths of inches withoutperforation 22 quality issues. Indeed, the instance of β being 21degrees permits an adjustment range (i.e., adjusting the distancebetween the support surface 40 and the cylinder 12 with perforation 22quality issues) of about two times, or about three times or about fourtimes more than the adjustment range when β is 35 degrees. Further, thelower the angle β, the less stress applied to the blade 20.

In one embodiment, the blade 20 can be in a cantilevered position. Thecantilevered position can allow for the blade 20 to flex at or near itsdistal end. More specifically, as the anvil 16 cooperates with the blade20, the distal end of the perforating blade flexes against the anvil 16to create the line of weakness 21 in the web 14. The blade 20 can bemade of tungsten carbide or other suitable material and is commerciallyavailable from The Kinetic Company. The blade 20 can be coated withmaterials to enhance its strength and wear resistance (also referred toas machine life). For example, in one embodiment, the blade 20 can besubject to plasma-enhanced chemical vapor deposition to deposit a thinfilm of material on the surface of the blade 20. Materials that can beused to prolong the machine life of the blade 20 can include titaniumoxide and ceramic coatings. Generally, the anvil 16 is a substantiallyhardened surface that does not flex or minimally flexes when incontacting engagement with the blade 20.

As previously disclosed, the support 18 can be in any orientation withrespect to the cylinder 12 that allows the blade 20 and anvil 16 tocooperate in contacting relationship to impart one or more perforations22 onto the web 14, as shown in FIG. 15 . Also shown in FIG. 15 , theweb 14 progresses in the MD, which is also the direction of rotation ofthe cylinder 12. Further, the support 18 can comprise a blade 20 thatcan be made up of a single-continuous blade or a plurality of bladesegments extending in an end-to-end relationship across the length SL ofthe support 18, as illustrated in FIGS. 13 and 16 respectively. That is,a support 18 can comprise a plurality of blade segments 20 that abut oneanother in length-wise fashion to act similar to a continuous blade.Alternatively, the plurality of blade segments 20 can be spaced suchthat at least one blade 20 is not in contact with an adjacent blade 20.Still further, the plurality of blade segments 20 can be spaced suchthat no one blade 20 is in contact with another blade 20 across thelength SL of the support 18.

As illustrated in FIGS. 17 and 18 , the blade 20 can comprise aplurality of teeth 36 and one or more recessed portions 38. Theplurality of teeth 36 and/or recessed portions 38 can be machined intothe blade 20, or one or more blades 20 can be assembled to produce oneor more recessed portions 38 and one or more teeth 36. As previouslydisclosed, each tooth 36 can have a length TL and a height TH and eachrecessed portion 38 can have a length RL. Each recessed portion 38 canbe separated by an adjacent notch length NL. The tooth height TH can bedesigned to obtain the desired perforation characteristics. In oneembodiment, the tooth height TH can be from about 0.005 inches to about0.500 inches, including every 0.001 inches therebetween. Further, thespacing of the one or more teeth 36 and one or more recessed portions 38can relate to the spacing of each perforation 22 and bond area 23 alongthe line of weakness 21 in the web 14. Thus, the spacing of the one ormore teeth 36 and one or more recessed portions 38 can be such thatevenly spaced perforations 22 are produced across the line of weakness21 in the web 14. This will be discussed in greater detail below.Alternatively, or in addition to a notched blade 20, the blade 20 cancomprise a smooth-edge, as shown in FIG. 13 . Generally, a notched blade20 cooperates in contacting relationship with a smooth-edge anvil 16, asshown in FIG. 18 .

Referring now to FIG. 19 , as can be understood by considering thepresent disclosure, a blade 20 and/or an anvil 16 can comprise one ormore teeth 36 and one or more recessed portions 38 for making a line ofweakness 21 comprising one or more perforations 22 and bond areas 23 inthe web 14. In one embodiment, the blade 20 disposed on the support 18comprises one or more teeth 36 and one or more recessed portions 38, andthe cylinder 12 comprises an anvil 16 in a wave-form shape. Due to thewave-form shape of the anvil 16, the rotation of the anvil 16 toward theblade 20, and the length of the one or more teeth 36 and the one or morerecessed portions 38, a certain perforation length PL, as shown in FIGS.19 and 22 , can be imparted to the web 14. For example, in oneembodiment, the length of the one or more teeth 36 and the one or morerecessed portions 38 are uniform in length. The uniform length of theone or more notches 36 and the one or more recessed portions 38 canresult in non-uniform perforation lengths PL due to the curvilinearshape of the anvil 16. By “uniform” is meant that the lengths aresubstantially equal or within about 15% or less of each other. By“non-uniform” is meant that two or more lengths are not equal or aregreater than about 15% of one another.

Therefore, in one embodiment, a perforating apparatus 10 can be designedto make a line of weakness 21 comprising one or more perforations 22having a substantially uniform perforation length PL. Alternatively, orin addition to uniform perforation lengths PL, the space between eachperforation 22, the bond area 23 can have a non-perforation length NP,where the NP can be substantially uniform. As previously disclosed withrespect to FIG. 1 , the perforating apparatus 10 can comprise a cylinder12 that rotates about a longitudinal cylinder axis 24 and a fixedsupport 18 between which a web 14 is advanced in the machine directionMD. More specifically, a wave-form shaped anvil 16 disposed on thecylinder 12 rotates and engages in contacting relationship with astraight, notched blade 20 disposed on the fixed support 18.

Referring to FIG. 19 , the anvil 16 is depicted schematically as acontinuous line, but can be any size fit for the cylinder 12 of aperforating apparatus 10, and can be made up of a plurality ofindividual anvil segments disposed on the cylinder 12 to form a shapedline of weakness 21 in the web 14. The wave-form (also referred to asshaped or curvilinear or nonlinear) shape of the anvil 16 can beprimarily dependent on the desired shape of the line of weakness 21 inthe finished web 14. The blade is schematically depicted as a straightpiece comprising one or more teeth 36 and one or more recessed portions38 with variable lengths. As stated above, the blade 20 and anvil 16cooperate in contacting relationship to perforate the web. Stillreferring to FIG. 19 , each tooth 36 has a length TL and can beseparated by a recessed portion 38 that also has a length RL. The hashmarks 42 on the anvil 16 indicate the end positions of each tooth 36based on the tooth length TL. Further, dashed lines 44 connect the hashmark 42 corresponding to each tooth 36 and, more specifically, the endpositions of each tooth 36. If a uniform perforation length PL isdesired, the tooth length TL and corresponding recessed length RL mustaccount for the shape of the anvil 16. As shown in FIG. 19 , the hashmarks 42 placed along the anvil 16 can be such that a uniform line ofweakness is imparted to the web 14. However, as shown by following thedashed lines 44 from the blade 20 to the anvil 16, to achieve uniformperforation lengths PL and/or non-perforated lengths NP, the lengths ofthe teeth 36 (or recessed portions 38) must vary along the length of theblade 20. For example, tooth length TL₁ is longer than TL₂, as shown inFIG. 19 , yet each produce a perforation having substantially the sameperforation length LP along the shaped anvil 16. Similarly, RL₁ islonger than RL₂, but such spacing or non-perforation portion producesubstantially uniform non-perforated lengths NP along the shaped anvil16.

Each tooth length TL can be individually predetermined such that itsprojected contacting relationship onto the anvil 16 delimits a length ofthe anvil 16 substantially equal to a desired perforation length PL inthe web 14. Each recessed portion length RL is individuallypredetermined such that its projected relationship with respect to theanvil 16 delimits a length of the anvil 16 substantially equal to adesired bond area having non-perforated length NP in the web 14. Forexample, each tooth length TL and recessed portion length RL can bedesigned such that the lines of weakness 21 in the web 14 comprisesperforations 22 that are longer at the edge of the web 14 compared tothe perforations toward the middle of the web 14, or bond areas 23 thatare shorter near the edge compared to the bond areas toward the middleof the web 14.

Referring now to FIGS. 20 and 21 , the tooth length TL and recessedportion length RL for an individual tooth 36 and recessed portion 38 onthe blade 20 can be calculated. In one example embodiment, the toothlength TL or the recessed portion length RL can be determined by firstmeasuring or predetermining a desired perforation length PL ornon-perforation length NP, as shown between adjacent hash marks 42.Next, connect adjacent harsh marks 42 with a straight line 46 andintersection the straight line 46 with a line 48 substantially parallelto the outside edge of the blade 20 forming an angle E. The straightline 46 should intersect the substantially parallel line 48 at a hashmark 42 so that the angle c is less than about 90 degrees. Assuming thatthe tooth 36 and/or recessed portion 38 has a surface that issubstantially parallel to the outer surface 30 of the cylinder 12, thetrigonometry of a right triangle can be used to calculate the toothlength TL and the recessed length RL. More specifically, still referringto FIG. 20 , the tooth length TL or recessed portion length RL can becalculated as the desired perforation length PL or non-perforationlength NP times the cosine of the angle E. Similarly, if the a certaintooth length TL or recessed portion length RL is known, the perforationlength PL or non-perforation length NP can be calculated using thegeometry of a right triangle. Thus, the notch length NL and recessedportion length RL can be determined for any adjacent harsh marks 42.Additionally, one of ordinary skill in the art would understand that ifthe blade 20 was not parallel to the outer surface 30 of the cylinder12, the resulting triangle would not have a right angle and more advancetrigonometry such as the law of sines, law of cosines, and law oftangents could be used to determine the angles and lengths.

Further to the above, in one embodiment, the perforating apparatus 10can comprise a shaped anvil 16, disposed on the rotating cylinder 12,comprising a plurality of teeth 36 and one or more recessed portions 38,and a blade 20 having a substantially smooth edge, not shown. Theperforating apparatus 10 imparts a line of weakness 21 onto the web 14.The line of weakness 21 will have perforations 22 and bond areas 23 thatdirectly correspond to the teeth 36 and recessed portions 38 of thenotched, shaped anvil 16. Stated another way, when the shaped anvil 16is notched, having one or more recessed portions 38 and one or moreteeth 36, the location of the recessed portions 38 will substantiallycorrespond to the location of bond areas 23 on the line of weakness 21and the location of the teeth 36 will substantially correspond to thelocation of the perforations 22 on the line of weakness 21. Thus, whenthe shaped anvil 16 is notched, the design of the recessed portions 38and teeth 36 should be done in a manner to directly reflect the desiredcharacteristics of the line of weakness 21.

An example embodiment of the web 14 produced by the present disclosureis shown in FIG. 22 . The web 14 can comprise one or more lines ofweakness 21. The line of weakness 21 can be substantially the same orsimilar to the curvilinear shape as that of the anvil 16, as wasdiscussed more fully above. The curvilinear line of weakness 21 cancomprise a plurality of perforations 22 and bond areas 23 betweenadjacent perforations 22. Each of the plurality of perforations 22 has aperforation length PL that can be substantially the same or differentwith respect to each other perforation length PL across the curvilinearline of weakness 21. Similarly, between each adjacent perforation 22 canbe a bond area 23 having a non-perforation length NP that can besubstantially the same or different relative to other and/or adjacentbond areas. Substantially can refer to the degree of similarity betweentwo comparable units, and, more specifically, refers to those comparableunits that are within about 15% of one another. Further, the pluralityof perforations 22 can protrude through one or more plies of the web 14.

As previously stated, each of the plurality of perforations has aperforation length and each of the bond areas has a non-perforationlength. In one example embodiment at least two of the perforationlengths are substantially equal. In another example embodiment, at leasttwo of the non-perforation lengths are substantially equal. In yetanother example embodiment at least two of the non-perforation lengthsare substantially unequal and at least two of the perforation lengthsare substantially unequal. In still another example embodiment, thecurvilinear line of weakness 21 can comprise at least one wavelength 34,and the one or more perforations 22 and bond areas 23 can be imparted tothe web 14 such that the perforation lengths PL near the edge of the web14 are longer than the perforation lengths PL near the middle of the web14 and/or the non-perforation lengths NP are shorter near the edge ofthe web 14 and longer near the middle of the web 14. Similarly, theperforations 22 and bond area 23 can be imparted to the web 14 such thatthe perforation lengths PL are substantially the same at the crest andtrough of the wavelength 34 and different between the crest and thetrough of the wavelength 34. Further, the perforations 22 and bond area23 can be imparted to the web 14 such that the non-perforation lengthsPL are substantially the same length at the crest and trough of thewavelength 34 and a different length between the crest and the trough ofthe wavelength 34.

A curvilinear line of weakness 21 can allow manufacturers to create aproduct that consumers can more easily and readily interact with. Forexample, a notched blade 20 or notched anvil 16 can be designed suchthat a shaped line of weakness 21 can tear more easily than, or at leastas easy as, a straight line of weakness 21. Generally, the ease withwhich an absorbent sheet product is torn at the line of weakness isdirectly associated with the tensile strength of the line of weakness.It is known that the lower the perforation tensile strength, the easierthe absorbent sheet product will separate at the line of weakness. Thefollowing data, shown in Table 1 below, illustrates the difference inthe perforation tensile strength required to tear a shaped, alsoreferred to as curvilinear or nonlinear, line of weakness 21 as comparedto that of a straight, also referred to as linear, line of weaknessacross a full sheet of absorbent tissue product.

The data shown in Table 1 was gathered using the Tensile Strength TestMethod as outline below. Generally, the data shows that the peak tensilestrength for a shaped line of weakness is less than the peak tensilestrength for a straight line of weakness. The peak tensile strength isthe maximum force reached along the line of weakness upon completelytearing the line of weakness. As evidenced by Table 1 below, generally,the peak tensile strength of a shaped line of weakness is from about 1%to about 40% less than the peak tensile strength of a straight line ofweakness imparted to the web 14 under similar manufacturing conditions,such as blade tooth length and recessed portion length. Stated anotherway, a shaped line of weakness imparted by the apparatus and method ofthe present disclosure can have a peak tensile strength that isgenerally at least about one percent and/or at least about 5% and/or atleast about 10% and/or at least about 20% less than the peak tensilestrength of a straight line of weakness.

Similar to the above, Table 1 also illustrates that the failure TEA(total energy absorbed) is generally less for a shaped line of weaknessas compared to a straight line of weakness. The failure TEA is the areaunder the curve between the point of initial tensioning of the sanitarytissue product to the point at which the shaped line of weakness hasfailed. The failure point of the shaped line of weakness is designatedby the tension falling below 5% of the peak load. As evidenced in Table1, generally, the failure TEA of the shaped line of weakness is fromabout 1% to about 50% and/or about from about 1% to about 30% and/orabout 1% to about 20% less than the failure TEA of the straight line ofweakness.

TABLE 1 % Difference in Full Sanitary % Difference Full Sanitary PeakLoad Tissue Product in Failure Blade Tissue Product from Sheet (4″) LineTEA from Recessed No. of Blade Shaped Anvil Shaped Anvil Sheet Line ofStraight Line of Weakness Straight Line Portion Recessed Tooth AmplitudeWavelength Weakness Peak of Weakness Failure TEA of Weakness LengthPortions per % Bond Length (inches) (inches) Load (grams) (control) (g *in/in) (control) (inches) 4.5″ Blade Area (inches) 0 0 604 Control 49.0Control 0.032 38 27% 0.083 0.06 1.35 545 −10% 42.0 −14% 0.032 38 27%0.083 0.10 1.35 593  −2% 49.3    1% 0.032 38 27% 0.083 0.15 1.35 608   1% 45.7  −7% 0.032 38 27% 0.083 0.17 0.90 551  −9% 39.5 −19% 0.032 3827% 0.083 0.17 1.35 579  −4% 44.2 −10% 0.032 38 27% 0.083 0.19 1.35 585 −3% 43.1 −12% 0.032 38 27% 0.083 0.22 1.35 611    1% 44.3 −10% 0.032 3827% 0.083 0.38 1.56 592  −2% 46.5  −5% 0.032 38 27% 0.083 0.56 1.35 484−20% 32.9 −33% 0.032 38 27% 0.083 0.56 1.94 524 −13% 34.7 −29% 0.032 3827% 0.083 0 0 688 Control 60.2 Control 0.013 99 29% 0.032 0.06 1.35 456−34% 30.4 −49% 0.013 99 29% 0.032 0.10 1.35 716    4% 76.5   27% 0.01399 29% 0.032 0.15 1.35 609 −11% 52.0 −14% 0.013 99 29% 0.032 0.17 0.90516 −25% 39.2 −35% 0.013 99 29% 0.032 0.17 1.35 588 −15% 53.7 −11% 0.01399 29% 0.032 0.19 1.35 557 −19% 41.7 −31% 0.013 99 29% 0.032 0.22 1.35561 −18% 47.7 −21% 0.013 99 29% 0.032 0.38 1.56 599 −13% 56.0  −7% 0.01399 29% 0.032 0.56 1.35 428 −38% 28.4 −53% 0.013 99 29% 0.032 0.56 1.94492 −29% 37.0 −38% 0.013 99 29% 0.032 0 0 462 Control 30.3 Control 0.02633 19% 0.106 0.06 1.35 433  −6% 27.9  −8% 0.026 33 19% 0.106 0.1 1.35557   21% 51.7   71% 0.026 33 19% 0.106 0.15 1.35 456  −1% 27.9  −8%0.026 33 19% 0.106 0.17 0.9045 424  −8% 25.7 −15% 0.026 33 19% 0.1060.17 1.35 452  −2% 28.6  −6% 0.026 33 19% 0.106 0.1875 1.35 404 −12%22.1 −27% 0.026 33 19% 0.106 0.22 1.35 476    3% 30.6    1% 0.026 33 19%0.106 0.375 1.5625 476    3% 45.9   52% 0.026 33 19% 0.106 0.5625 1.35377 −18% 21.1 −30% 0.026 33 19% 0.106 0.5625 1.94 419  −9% 26.7 −12%0.026 33 19% 0.106 0 0 810 Control 86.8 Control 0.041 40 37% 0.069 0.061.35 668 −18% 73.2 −16% 0.041 40 37% 0.069 0.1 1.35 814    1% 89.1    3%0.041 40 37% 0.069 0.15 1.35 794  −2% 83.9  −3% 0.041 40 37% 0.069 0.170.9045 751  −7% 77.3 −11% 0.041 40 37% 0.069 0.17 1.35 785  −3% 79.3 −9% 0.041 40 37% 0.069 0.1875 1.35 840    4% 87.5    1% 0.041 40 37%0.069 0.22 1.35 771  −5% 79.6  −8% 0.041 40 37% 0.069 0.375 1.5625 778 −4% 81.6  −6% 0.041 40 37% 0.069 0.5625 1.35 667 −18% 57.7 −34% 0.04140 37% 0.069 0.5625 1.94 709 −13% 64.4 −26% 0.041 40 37% 0.069

Further, a shaped line of weakness 21 on a sanitary tissue paperproduct, for example, allows consumers to more easily grasp and dispensethe exposed sheet of the product due to the shaped line of weakness 21creating a series of tabs or a visually identifiable edge. Stillfurther, the shaped line of weakness 21 can allow consumers to readilydistinguish a product from other manufacturer's products by having avisually distinctive perforation, such as one that complements an embossor print pattern. FIGS. 23 A-Q illustrate various shapes of thecurvilinear line of weakness 21 that can be imparted to the web. One ofordinary skill in the art based on the aforementioned disclosure wouldunderstand that the shape of the line of weakness 21 is due in part tothe shape of the shaped anvil 16 or shaped blade 20 disposed on therotating cylinder 12. Thus, the shapes shown in FIGS. 23A-Q could alsobe the profiles of the shaped anvil 16 or shaped blade 20 disposed onthe rotating cylinder 12. Generally, the profiles depicted in FIGS. 23A-Q can be described as exhibiting a sinusoidal shape, as being a groupof two or more linear elements each connecting at a single inflectionpoint with an adjacent linear element, or a combination of curvilinearand linear elements.

In another example embodiment, the cylinder 12 can comprise a shapedblade 20 and the support 18 can comprise a straight, linear anvil 16,not shown. Likewise, in another example embodiment, the cylinder 12 cancomprise a shaped blade 20 and the support 18 can comprise a straight,linear blade. The above description applies to either of the recitedconfigurations.

Tensile Strength Test Method

Elongation, Tensile Strength, TEA and Tangent Modulus are measured by orcalculated from data generated by a constant rate of extension tensiletester with computer interface (a suitable instrument is the EJA Vantagefrom the Thwing-Albert Instrument Co. Wet Berlin, N.J.) using a loadcell for which the forces measured are within 10% to 90% of the limit ofthe load cell. Both the movable (upper) and stationary (lower) pneumaticjaws are fitted with smooth stainless steel faced grips, with a designsuitable for testing the full width of one sheet material. For example,the Thwing-Albert item #734K grips are suitable for testing a sheethaving about a four inch width. An air pressure of about 60 psi issupplied to the jaws.

Unless otherwise specified, all tests described herein, including thosedescribed in the detailed description, are conducted on samples thathave been conditioned in a conditioned room at a temperature of 73°F.±2° F. (23° C.±1° C.) and a relative humidity of 50% (±2%) for 2 hoursprior to the test. All tests are conducted in such conditioned room(s).All plastic and paper board packaging materials must be carefullyremoved from the paper samples prior to testing. If the sample is inroll form, remove at least the leading five sheets by unwinding andtearing off via the closest line of weakness, and discard before testingthe sample. Do not test sheet samples with defects such as perforationskips, wrinkles, tears, incomplete perforations, holes, etc.

A full finished product width sheet sample of a paper towel or bathtissue product is cut so that a perforation line passes across the sheetparallel to each cut in the width dimension. More specifically, take twoadjacent sheets separated by a line of weakness (comprising one or moreperforations), and cut a test sample to include at least a portion ofthe two tissue sheets. The cuts should be made across the width of thesheet generally parallel to the line of perforation and equally aboutthe line of perforation. For example, the first cut is made at least twoinches above the line of weakness comprising perforations and anothercut is made on the other side of the line of weakness at least twoinches from the line of weakness comprising perforations. At all timesthe sample should be handled in such a manner that perforations are notdamaged or weakened. The prepared sample is placed in the grips so thatno part of the line of weakness is touching or inside the clamped gripfaces. Further, the line of weakness should be generally parallel to thegrip. Stated another way, if an imaginary line were drawn across thewidth of the sheet connecting the two points at which the line ofweakness crosses the edge of the sheet, the imaginary line should begenerally parallel to the longitudinal axis of the grips (i.e.,perpendicular to the direction of elongation).

Program the tensile tester to perform an extension test, collectingforce and extension data at an acquisition rate of 20 Hz as thecrosshead raises at a rate of 4.00 in/min (10.16 cm/min) until thespecimen breaks (i.e., when the test specimen is physically separatedinto two parts). The break sensitivity is set to 98%, i.e., the test isterminated when the measured force drops to ≤2% of the maximum peakforce, after which the crosshead is returned to its original position.

Set the gage length to 2.0 inches. Zero the crosshead position and loadcell. Insert the sheet sample into the upper and lower open grips suchthat at least 0.5 inches of sheet length is contained each grip. Verifysheet sample is properly aligned, as previously discussed, and thenclose lower and upper grips. The sheet sample should be under enoughtension to eliminate any slack, but less than 5 g of force measured onthe load cell. Start the tensile tester and data collection.

The location of failure (break) should be the line of weakness. Eachsample sheet should break completely at the line of weakness. The peakforce to tear the line of weakness is reported in grams. If the locationof the failure (break) is not the line of weakness, disregard the dataand repeat the test with another sheet sample. Note, the output resultis for the entire sheet sample and therefore does not need to benormalized.

Adjusted Gage Length is calculated as the extension measured at 5 g offorce (in) added to the original gage length (in).

Peak Tensile is calculated as the force at the maximum or peak force.The result is reported in units of g/in, to the nearest 1 g/in. Note theoutput results are for the entire sheet sample width and is notnormalized.

Failure Total Energy Absorption (Fail_TEA) is calculated as the areaunder the force curve integrated from zero extension to the extension atthe “failure” point (g*in), divided by the adjusted Gage Length (in).The failure point is defined here as the extension when the tensionforce falls to 5% of the maximum peak force. This is reported with unitsof g*in/in to the nearest 1 g*in/in. Again, note that the output resultsare for the entire sheet sample width.

Repeat the above mentioned steps for each sample sheet. Four samplesheets should be tested and the results from those four tests should beaveraged to determine a reportable data point. The data generated inTable 1 above represents data points of an average of four measuresgenerated by the above test method.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numerical values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm.”

Every document cited herein, including any cross referenced or relatedpatent or application, is hereby incorporated herein by reference in itsentirety unless expressly excluded or otherwise limited. The citation ofany document is not an admission that it is prior art with respect tothis disclosure or that claimed herein or that it alone, or in anycombination with any other reference or references, teaches, suggests,or discloses any such invention. Further, to the extent that any meaningor definition of a term in this document conflicts with any meaning ordefinition of the same term in a document incorporated by reference, themeaning or definition assigned to that term in this document shallgovern.

While particular embodiments of the present disclosure have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the disclosure. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this disclosure.

What is claimed is:
 1. A rolled absorbent product comprising: a webcomprising a sinusoidal-shaped line of weakness, the sinusoidal-shapedline of weakness comprising a plurality of perforations and a firstamplitude; and wherein the sinusoidal-shaped line of weakness has a peakforce to tear of less than 840 grams, as measured according to theTensile Strength Test Method.
 2. The rolled absorbent product of claim1, wherein the sinusoidal-shaped line of weakness has a peak force totear of at least 377 grams, as measured according to the TensileStrength Test Method.
 3. The rolled absorbent product of claim 1,wherein the sinusoidal-shaped line of weakness has a failure totalenergy absorbed (TEA) of less than 89.1 grams*inch/inch.
 4. The rolledabsorbent product of claim 3, wherein the sinusoidal-shaped line ofweakness has a failure total energy absorbed (TEA) of at least 21.1grams*inch/inch.
 5. The rolled absorbent product of claim 1, wherein thesinusoidal-shaped line of weakness has a wavelength of between 0.90inches and 1.94 inches.
 6. The rolled absorbent product of claim 1,wherein the web has multiple sinusoidal-shaped lines of weakness and thewavelengths of each sinusoidal-shaped line of weakness have an amplitudeof less than about 50% of the distance between adjacentsinusoidal-shaped lines of weakness.
 7. The rolled absorbent product ofclaim 1, wherein perforation lengths of the plurality of perforationsare between 0.032 inches and 0.106 inches.
 8. A rolled absorbent productcomprising: a web comprising a curvilinear line of weakness, thecurvilinear line of weakness comprising a plurality of perforations anda first amplitude; and wherein the curvilinear line of weakness has apeak force to tear of less than 840 grams, as measured according to theTensile Strength Test Method.
 9. The rolled absorbent product of claim1, wherein the curvilinear line of weakness has a peak force to tear ofat least 377 grams, as measured according to the Tensile Strength TestMethod.
 10. The rolled absorbent product of claim 1, wherein thecurvilinear line of weakness has a failure total energy absorbed (TEA)of less than 89.1 grams*inch/inch.
 11. The rolled absorbent product ofclaim 3, wherein the curvilinear line of weakness has a failure totalenergy absorbed (TEA) of at least 21.1 grams*inch/inch.
 12. The rolledabsorbent product of claim 1, wherein the curvilinear line of weaknesshas a wavelength of between 0.90 inches and 1.94 inches.
 13. The rolledabsorbent product of claim 1, wherein the web has multiple curvilinearlines of weakness and the wavelengths of each curvilinear line ofweakness have an amplitude of less than about 50% of the distancebetween adjacent curvilinear lines of weakness.
 14. The rolled absorbentproduct of claim 1, wherein perforation lengths of the plurality ofperforations are between 0.032 inches and 0.106 inches.